Research in South Africa will complement the candidate's ongoing exploration of structure-function relations int he brain. The investigator proposes to extend his recent findings that systematically relate avian brain structure, across species and within species, to capacity for song learning. In these studies, associations between brain nucleus morphology and characteristics of song provide a novel approach to identifying nucleus function. The investigators will look for these associations across many bird species: across families, across species within a genus, and across individuals within a species. A unique focus will be to study the brains of females in which mate selection uses song perception. The investigators' current data demonstrate the power of this approach in Acrocephalus species that breed in eastern Europe, some of which migrate to subsaharan Africa. Access to Acrocephalus species with distinct song characteristics that breed in Africa is essential to extend the investigators' initial work on the song system. Work with these species will also allow them to apply this approach to another behavioral system, to take these studies to spatial memory in birds beyond the lab to a natural behavior. They will compare hippocampal anatomy in species that do and do not migrate. Finally, to complete any of these studies, they must establish phylogenetic relationships between species by analyses of mitochondrial DNA. All aspects of this work will involve close collaboration with experts in avian systematics at the Fitzpatrick Institute of African Ornithology, University of Cape Town, over the course of three visits, one (6 months) to identify study sites, work out molecular procedures, and begin taping males, and two later (3-month) visits during reproduction to record and catch additional species. Issues of motor and spatial learning, and of sex differences and individual health. Comparative study may give new insights in neural features associates with each.